In the field of logistics, that is the field of movement and supply of produce and materials, in particular in the transport of intermediate and finished products, containers have been developed which safely protect from physical damage a wide variety of product. However, certain types of products, such as pharmaceutical and food products not only need protection from physical shock and pressures but also require temperature stability during transportation; otherwise goods can be damaged and be unusable, whether such damage is apparent or not.
For example, in the pharmaceutical industry, product often needs to be maintained within a temperature range: product may be packed in relatively small containers, which containers are relatively fragile—accordingly insulation must provide both physical and thermal stability. Small cargos of pharmaceuticals can be extremely valuable, not just in financial terms, but possibly also in terms of health. Destruction by poor handling of pharmaceuticals can have far-reaching consequences. Equally, in the food industry, fish suppliers will often have chilled fish boxes which are designed to accept, say 20 Kg of product. The fish must be maintained at low temperatures, yet will be placed in containers which require a high degree of strength to prevent spillage.
As the standards of living increases, in developed markets, for example in Europe and North America, tropical foods—that is foods grown in far-away tropical places—are increasingly being stocked by supermarkets, delicatessens and the like. Short pick to distribution centre times in the producing country are matched by air carriers taking goods to the countries of consumption in similar lengths of time, whereby it is not uncommon for fruit to be on the plates of householders within two to three days of having been picked in a far-away country.
However, air transport poses a particular problem: Goods can be transported in tropical heat, packaged and placed upon pallets and the like containers whereby they are presented in aircraft style containers. Such goods may be left on runways at extreme temperatures (+40° C.) and then placed within a hold where low pressures and low temperatures exist during flight. At a destination airport the temperatures may well be sub-zero. A corollary to this is the production of temperature sensitive pharmaceuticals in a “developed” country which pharmaceuticals must be transported to another side of the world with similar temperature variations.
Both the above scenarios place transport managers in difficult positions. For air haulage, containers should weigh little, make use of non-rectangular hold spaces within aircraft; for the goods, they must be protected from shock, be maintained within a narrow temperature range, sometimes being equipped with temperature data loggers whereby a record of temperature within a container may determine whether or not a pharmaceutical is destroyed prior to use because of poor temperature handling. Refrigeration units may be provided with a container whereby temperatures maybe maintained, but then a source of electrical power or fuel for a powered generator is required. An example of such a temperature control system is shown in CN20136863 to Hefei Midea Royalstar Refigeration Company.
To simplify transport with respect to airports, planes and handling equipment, there have been developed aircraft Unit Load Devices (ULDs) which comprise any type of pallet or container that can easily be loaded to the aircraft by a ground handler. Aircraft ULDs are units which interface directly with an aircraft loading and restraint system, without the use of supplementary equipment. There are pre-defined ULDs, such as LD3, LD7, which correspond to standard configurations and can be utilised on certain types of aircraft. There are still further ULDs that are shaped such that they have a rectangular base yet are not generally cylindrical, that is to say they extend outwardly, beyond the sides of the base, as they extend upwardly from the base. KR 20080100401 provides a multi combined packing container is provided to improve the products value of the fresh food through low temperature refrigeration circulation in the current fresh food circulation system. The multi combined packing container comprises first, second third and fourth packing materials—arranged in a fashion similar to a Russian doll assembly, wherein the third packing material is a form of refrigerant pack and is inserted inside the second packing material; the fourth packing material is inserted inside the third packing material.
Other known forms of chilling products such as ice packs comprise polymer coolants packaged within bags can provide simple means to cool products. Coolant gels may also be employed, being inserted into plastics containers, typically being, but when packed do not necessarily offer sufficient heat transfer. However, in the nature of transport containers, the gel packs can move or otherwise become dislodged from a selected place whereby an inappropriate temperature gradient can occur, whereby a required temperature for a medicine, vaccine, food or other product is not maintained; products such as vaccines that have not been maintained within a required temperature range during transport must be disposed of without use. It will be appreciated that if a container of, say, a freezable gel is knocked from a normal placement position and leaks to a joint between two panels of a container, the temperatures encountered within aeroplanes is substantially below 0° C.; subsequent freezing and cooling can damage the container irreparably and damage contents within.
It is notable that there are few passive thermal exchange devices for cargo containers; few can provide sufficient cooling properties; few can remain where placed during transport as a matter of course. Further, in terms of containers, cooling systems need to be easily removable and be capable of being packed flat, along with an associated insulating cargo containers; either they are rigid yet not collapsible or are collapsible yet easily damaged when shifted by fork-lifts and other and/or are complex to assemble.